1. Field of the Invention
The present invention generally relates to a data structure and operation method for A/V disks and, more particularly, to a file structure for recording navigation data generated by editing or newly created A/V data and a method using the file structure to play the A/V data.
2. Related Art
The technique of using disks (such as CD's or floppy disks) to store A/V data is already well known. Two files have to be stored in the disk in order to successfully play the A/V data in an A/V player: one is an A/V data file for recording A/V contents, such as the “VRO file” in the DVD-video recording specification; the other is a navigation file upon which necessary navigation data for playing A/V data is recorded, such as the “.ifo file” in the DVD-video recording specification. This type of navigation files usually stores: (1) the playing time and related addresses in the A/V file for the A/V data; (2) original program information files; and (3) user defined play lists. The playing program in the A/V player plays the A/V data stored in the A/V data file according to the information recorded in the navigation file.
Please refer to FIG. 1 for the structure of a traditional navigation file. Various navigation data in the navigation file are first recorded using unique tables, and then a manager information table disposed in the beginning of the navigation file is used to record a start address for every table in the navigation file.
The structure of this type of traditional navigation file has some disadvantages:                1. When adding either still or movie A/V data (such as recording programs), a still or movie A/V information table has to be updated and so does the whole navigation file.        2. When users edit or change the play list, a play list information table has to be updated and so does the whole navigation file. If there is not enough space in the disk or a write-once optical disk is used, continuous updating will cause damage to the disk and shorten its life span, especially for write-once optical disk. This type of updating method that requires re-writing the navigation file each time will waste disk space. This is because each table in the navigation file uses an address-recording method (the data at the beginning address are recorded in the manager information table). So, whenever a table is updated, the beginning address needs to be reset and, therefore, the navigation file contents have be modified and updated again, abandoning the old navigation file.        